DE19541816C2 - Diagnostic system for a motor vehicle - Google Patents

Description

The present invention relates to a diagnostic system for a vehicle where data from an electronic tax unit can be read out, which instal in the vehicle is. The invention particularly relates to a diagnosis system which is used for different types of protocols for the data transmission or data communication is applicable.

In the recent past, electronic tax is tion of a motor vehicle has become increasingly complicated. Diagnostics is essential for the diagnosis of the vehicle system, which data of electronic control units, which in installed in the vehicles.  

This diagnostic system is usually portable and universal sell usable. A car mechanic can then easily check the control system of the vehicle. The mei Most diagnostic systems are equipped with a memory cassette which can be separated from the system. The Memory cartridge contains a recording medium which Diagnostic programs stores the types and types of in correspond to certain years of manufactured vehicles etc. The diagnostic system with the memory cartridge represents a da ten connection to the electronic control unit in the Vehicle from which the data is read. A sol ches system, or diagnostic device, is in the open Japanese Patent Application Laid-Open No. 1-210844.

There are many types of electronic control units, wel be installed in motor vehicles. These units ver apply different types of transmission systems and Interfaces. Motor vehicle manufacturers see differ che communication or transmission protocols for ver different types of vehicles. That fact makes it necessary that repair shops have diagnostic facilities equip it with hardware so that it can be used for different purposes Communication protocols for every vehicle manufacturer or can be used for any type of electronic control unit are. Equipping this facility for all communica cation logs is a big one for the repair shop economic burden.

In order to solve this problem, the disclosed japa discloses African patent JP-A-3-111733 an adapter for Umwan delle of signals from a data processing circuit can be solved in a diagnostic device. This will make a Part of the circuit of the diagnostic device for the data exchange with a control system of a motor vehicle interchangeable. The diagnostic device is therefore different  Types of communication protocols can be used.

One type of diagnostic facility still requires under various additional hardware. This results in higher ones Total production costs. This can also lead to a mis slide in a repair shop if the additional che hardware for data exchange of the diagnostic device is assigned incorrectly. Such faulty compilation conditions often occur when diagnostic programs for under different types of motor vehicles, types of vehicles, which were made in certain years, and the like be exchanged.

DE-A-42 29 931 discloses a method for programming a bus-compatible electronic vehicle control unit, which contains a bus programming chip. The programming is done such that an application software via the bus protocol chip communicates by the bus protocol chip to the user application software "hidden" and a com communication interface is created.

US-A-5,278,759 describes a reprogramming method a non-volatile memory of a motor vehicle Computers over a serial communication link between one outside the computer Control device and the motor vehicle computer known. An interface circuit is provided in the vehicle, to receive the command signals from the portable controller process it the non-volatile memory allow to receive a new computer program code and save. The procedure follows a given one Transmission protocol that prevents the existing Computer program code erroneously deleted or overwritten becomes.  

US-A-5,107,428 describes a diagnostic device for an electronic control unit in a motor vehicle that adapts to different types of electronic control units is cash. For this purpose, the patent proposes the use of a multiple processor with two micro controllers, a master microcontroller and a slave microcontroller. Every Wed krocontroller includes a processor, counter, A / D converter and memory and carries one Self test through.

In "The Electronics Technician", No. 8/1991, pages 11 to 17 there is a uniform interface to Motor vehicle diagnostics described using a fixed, standardized protocol between to be able to provide the motor vehicle and a test facility. This unified Interface in the motor vehicle is realized in that it comprises two interfaces, a standardized for all manufacturers, which the transmission between the vehicle and the diagnostic device, and one in the diagnostic interface itself, which takes into account the manufacturer-specific system and a conversion between the manufacturer ler and the standard interface.

It is an object of the present invention to make a diagnosis to provide a system which is suitable for all types of vehicles installed electrical control units with under different communication protocols is suitable without having to change the hardware.

According to the present invention, a diagnostic system for a motor vehicle is provided which has several sensors for Detection of operating conditions of the vehicle and Er testify to vehicle operating signals, an electronic Control unit for controlling the vehicle and for generating of control signals which are related to the vehicle operating signals appeals, and multiple actuators and displays lamps that respond to the control signals, to operate the vehicle in optimal conditions, which each correspond to the operating conditions, whereby the system data in the electronic control unit reads and can transmit this data with a diagnosis device which responds to the control signals to the electronic control unit by comparing the transmission data with normal data stored in a memory diagnose, and one from the diagnostic facility  separable storage device for storing differ cher diagnostic programs and communication protocols, and at which the diagnostic system has the following features: an in the interfaces provided for the storage device circuit, which directly with the electronic control connected to adapt a logical function, which corresponds to each control signal, and by a transfer generate signal; Storage means for saving as different types of logic programs; an internal system Programming device which is based on the transmission signal responds to lo the memory means by reprogramming functions of the circuit based on design information tion to control the vehicle at high speeds diagnosis precisely, without the memory direction for different types of electronic devices exchanges.

The diagnostic system can also have a memory for storage different types of design information for the new have programming. The memory can be volatile Memory or an electronically erasable, non-volatile Be memory.

The diagnostic system may also include a recording medium point, which is provided in the storage device, to save the diagnostic programs.

The diagnostic system can also be an interface circuit have, which is provided in the storage device to the integrated circuit with the electronic control unit to connect.

According to the present invention, a diagnosis system is also provided stem for performing a diagnosis based on data, wel be read out from an electronic control unit,  performed, the electronic control unit a Has communication protocol and in a vehicle is installed with the following features: a main processor to carry out a virtual data exchange with the electronic control unit for diagnosis; and one Subprocessor for executing communication processing tion program to the communication protocol fits to the data exchange with the electronic tax Realize unit, with the sub-processor first Receives data from the main processor and the first data transmits to the electronic control unit and second Receives data from the electronic control unit and the second data to the main processor transfers to the virtu to realize data exchange.

The diagnostic system can also be one of the diagnostic system removable memory cartridge and a recording medium for Save the communication processing program sen. The recording medium can save a diagnostic program which is executed by the main processor.

In the system addresses of the communication processing management program and the diagnostic program a memory area of the main processor, and the comm The application processing program becomes the subprocessor sent before the communication processing program of the subprocessor is executed.

The diagnostic system can also be an interface circuit to connect the subprocessor with the electronic Have control unit.

Preferred embodiments of the present invention are in the following with reference to the drawings with further a details discussed. The figures show:  

Fig. 1 is a front view of a fault diagnosis apparatus according to the present invention, which is connected to an electronic control unit in a motor vehicle;

Fig. 2 is a circuit diagram in the form of a block diagram of the electronic control unit and the diagnostic device according to a first preferred embodiment of the present invention;

Fig. 3 is a circuit diagram in the form of a block diagram of the FPGA 45 of Fig. 2;

Fig. 4 is a flowchart for explaining the procedure of data exchange and the diagnostic method according to the first embodiment;

Fig. 5 is a circuit diagram in block diagram form the electronic control unit and the Fehlerdiagno seeinrichtung according to the second preferred exporting approximately of the present invention; and

FIGS. 6A and 6B are flow charts for explaining the flow of data exchange and the diagnostic method according to the second embodiment.

Fig. 1 shows a front panel of a portable diagnostic device 100 according to the present invention. The diagnosis device 100 is connected to an electronic control unit 300 , which is installed for diagnosis in a motor vehicle 200 . On the front panel, a liquid crystal screen 30 , a display device 31 made of light-emitting diodes and a keyboard 32 are provided. An input / output connector 33 and a circuit breaker 35 are provided on the top of the diagnostic device 100 . An adapter piece 34 extends from the input / output connector 33 . A memory cartridge 60 is inserted in the lower part of the diagnostic device 100 . The cassette 60 will be described later.

In order to diagnose an error which occurs in the control unit 300 , the following steps are carried out: first, the adapter piece 34 is connected to a connecting element 2 a of the control unit 300 ; then the Lei power switch 35 is turned on; third, certain keys of the keyboard 32 are entered; and finally, the diagnosis is carried out while watching the display of the display screen 30 .

The preferred embodiments use an engine control unit (ECU) 2 to be examined as the electronic control unit 300 , as shown in FIG. 2. In addition to engine control, the electronic control unit 300 can be used for the following purposes: control of power transmission of an engine, an automatic transmission, and the like; Control of the vehicle body, such as the air conditioning and various information management systems; Control of the vehicle, such as control of the suspension, cruise control (auto-cruise) and the like.

As shown in FIG. 2, the motor control unit 2 is a microcomputer with a voltage regulator 8 , which supplies predetermined constant voltages to the circuits and a driver 9 . The microcomputer comprises: a CPU 3 as a main processing unit; a ROM 4 which stores predetermined data, e.g. B. an engine control program and various memory maps; a RAM 5 which stores data obtained by processing output signals from different sensors; an input interface 6 to which these output signals are transferred; and an output interface 7 , which supplies control signals to various actuators. These components are interconnected via buses.

In the following data signals are specified, which are applied to the input interface 6 : a cooling temperature signal TW, which is generated by a cooling temperature sensor 10 ; a lean / rich signal λ, which corresponds to the air-fuel ratio and is generated by an oxygen sensor 11 ; an intake air amount signal Q generated by an intake air sensor 12 ; an ON / OFF signal SWa of an air conditioning switch 13 ; a vehicle speed signal S generated by a speed sensor 14 ; an ON / OFF signal SW1 of an idle switch 15 ; a throttle signal TrΘ, which is generated by a throttle sensor 16 , the signal TrΘ corresponding to an opening degree of the throttle; an ON / OFF signal SWn of a neutral switch 17 ; and an engine speed signal N generated by an engine speed sensor 18 .

These data signals are processed by the CPU 3 and written into the RAM 5 to control the calculations of the sizes. The CPU 3 reads the data from the RAM 5 to calculate various control quantities such as a pulse width for the fuel injection and an ignition timing. The CPU 3 generates the control signals which correspond to the control variables. The control signals are sent to the driver 9 via the output interface 7 at predetermined points.

The following components are connected to the driver 9 : a tank control device 19 for controlling the removal or emptying amount of the tank; an EGR actuator 20 for controlling the EGR size; an idle control actuator 21 for controlling an idle speed; an ignition coil 22 for supplying high voltage and igniting the ignition coil; and an injector 23 for injecting fuel into an engine. The driver 9 drives these components with the control signals which are fed to it via the output interface 7 in order to control the motor in each control area.

A self-diagnosis display device 24 is also connected to the driver 9 in order to display errors when these are discovered by a self-diagnosis function. The display device 24 has a number of lamps which flash at predetermined times or are switched on in a certain way. These light indicators correspond to the error codes which are read from the ROM 4 and in turn correspond to the error areas.

The RAM 5 has a backup RAM, to which an auxiliary power supply from a battery V _B is supplied via a controller 8 if the main power fails. The backup RAM stores values which it receives through error learning, corresponding error codes, etc.

The diagnostic device 100 can be used in a repair workshop, for example of a car dealer. The diagnostic device 100 has a control device 36 (microcomputer) and a voltage regulator 37 . With the voltage regulator 37 , the circuit breaker 35 is connected, which is also connected to the battery V _B via the adapter piece 34 . The removable storage cassette 60 with a ROM 61 is introduced into the control device 36 via the connecting device 38 .

The controller 36 includes a CPU 40 as a main processor, a RAM 41 , a timer 42 for generating a synchronization signal, input / output interfaces 43 and 44 and a communication interface (which will be described later). These components and the ROM 61 of the memory cartridge 60 are connected to one another via buses. The output signals of the sensors and switches of the ECU 2 are transferred to the input / output interface 43 via the output interface 7 . Depending on the output signals, the input / output interface 43 generates signals for switching on the LEDs of the display device 31 . The LEDs indicate ON or OFF states of the sensors and switches. A key input on the keyboard 32 generates signals which are supplied to the input / output interface 44 . The interface 44 generates signals which are supplied to the display screen 30 .

The first preferred embodiment uses a user programmable universal circuit (field-programmable gate arrangement; FPGA) 45 as the transmission or communication interface. The FPGA 45 is an integrated semiconductor circuit with reprogrammable logic functions. These functions can be reprogrammed on site using design information that applies to a communication protocol of the ECU 2 .

As shown in FIG. 3, the FPGA 45 has the following features: a memory 46 which stores the programmed content; Macro cells 47 , the logic functions of which depend on the content of the memory 46 ; a logic wiring block 48 which connects the macro cells 47 to data from the memory 46 ; an input / output wiring block 49 through which the macro cells 47 can accept external input and output signals; and a system-internal programming device 50 for managing the memory 46 . The memory 46 is either a volatile memory of the SRAM type or a non-volatile memory of the EEPROM type, the data of which can be electrically erased.

The memory cartridge 60 is intended to make the diagnostic device 100 flexible for general use and usable for different diagnostic objects, types of vehicles, communication protocols, etc. For this purpose, the ROM 61 stores a diagnostic start program (boot program) for the CPU 40 , a diagnostic program for an electronic control unit (ECU) 2 of a special motor vehicle and logic data for reprogramming the FPGA 45 . The ROM 61 need not necessarily save the boot program. A read-only memory (ROM) in which the boot program is stored can also be provided in the control device 36 .

The memory cartridge 60 has an input / output interface 62 which connects the FPGA 45 and the ECU 2 . Via transmission lines 63 a and 64 a are connected to the input / output interface 62 via the connecting device 38 . Furthermore, the transmission lines 63 a and 64 a are connected to the input and output interfaces 6 and 7 of the ECU 2 via the input / output connection device 33 and the adapter piece 34 .

The input / output interface 62 is used to convert signal levels, input / output powers, etc. to be suitable for any type of ECU 2 . The engine control units can be different in the transmission systems of the motor vehicles. Furthermore, such control units cannot be adapted via logic functions of the FPGA 45 . Transmission lines 63 b and 64 b are connected via the connecting device 38 to the input / output interface 62 , the transmission lines extending from the output connection and the input connection of the FPGA 45 . The input / output interface 62 can be replaced by wire connections of the transmission lines 63 a and 63 b and 64 a and 64 b. This replacement is possible when the signals between the ECU 2 and the FPGA 45 match.

In order to diagnose errors, the memory cassette 60 with the ROM 61 is inserted into the diagnostic device 100 . The ROM 61 stores the diagnosis program for the engine control unit (ECU) 2 of a certain motor vehicle and certain design data. The diagnostic device 100 is initialized, and the design data stored in the ROM 61 is transferred to the FPGA 45 . The FPGA 45 is reprogrammed with the design data so that it can be used for the diagnostic program and the communication protocol for the ECU 2 of the motor vehicle 200 . In this way, communication between the ECU 2 and the FPGA 45 becomes possible.

The flow chart shown in FIG. 4 describes the sequence of the diagnostic operation with the diagnostic device 100 .

To carry out the method: first the diagnostic device 100 is connected to the memory cartridge 60 via the adapter piece 34 with the ECU 2 ; and then the circuit breaker 35 is turned on to reset the CPU 40 which determines the entire system of the diagnostic device 100 . In this way, the entire system is initialized (step S101).

The initialization switches on the programming mode of the FPGA 45 in step S102. In the event that the memory 46 ( FIG. 3) of the FPGA 45 is an EEPROM, its data must first be erased. In step S103, the design data for forming the communication interface applicable to the communication protocol of the ECU 2 is read from the ROM 61 of the memory cartridge 60 . The design data is transferred to the FPGA 45 .

In step S104, it is checked whether the transfer of all design data has been completed. If it is not completed, data exchange continues in step S103. When it is completed, the programming mode of the FPGA 45 is turned off in step S105.

In the FPGA 45 , as shown in FIG. 3, the native programming device 50 determines the logic functions of the macro cells 47 . This decision is made in accordance with the design data stored in the memory 46 when the programming mode is ON. Furthermore, the logical wiring block 48 and the input / output wiring block 49 are connected to each other with the connection information. When the data exchange is completed, the FPGA 45 forms the communication interface which can be used for the communication protocol of the ECU 2 . The FPGA 45 then becomes active so that communication between the CPU 40 and the ECU 2 is possible when the programming mode is turned OFF.

In step S106, the FPGA 45 transmits a response request via the connecting line 63 b, the input / output interface 62 of the memory cartridge 60 , the transmission line 63 a of the diagnostic device 100 and the adapter piece 34 to the ECU 2 . This data exchange is carried out with the communication protocol of the ECU 2 . The FPGA 45 then waits for the response of the ECU 2 in step S107.

The response request is forwarded to the ECU 2 via the input interface 6 . Then the ECU 2 transmits a response via the adapter piece 34 , the transmission line 64 a, the input / output interface 62 , the transmission line 64 b and the FPGA 45 to the CPU 40 .

If the CPU 40 receives the answer in step S107, the CPU 40 executes a diagnostic program in step S108. While this program is running, a message is displayed on the display screen 30 indicating that the diagnosis can now begin and the system goes into a keypad wait mode.

For example, to check a battery voltage, a conditioner gives the battery voltage diagnostic mode buttons, e.g. B. "F", "0", "1" and "ENT" on the keyboard 32 . This diagnostic mode is interpreted by the CPU 40 , which requests battery voltage data from the ECU 2 via the FPGA 45 .

Depending on this request, the ECU 2 searches for an address in the RAM 5 which corresponds to the request in order to read out data. This data is transmitted to the diagnostic device 100 .

Upon receipt, the diagnostic device 100 performs data processing, e.g. B. a binary-decimal conversion. The processed result is displayed on the screen 30 . The operator checks the battery voltage via the display and continues to diagnose further points as necessary by entering appropriate keys.

As described above, the diagnostic device according to the first embodiment for different types of electronics control units. This will do so achieved that for the communication protocols with un different data formats, transmission and reception times and the same suitable storage cartridges who replaced the. So there is no need for additional diagnostic tools different hardware for the communication protocols of the electronic control unit are provided. From that he there is a very efficient diagnostic operation.

The design data for the FPGA 45 need not necessarily be stored in the RAM 61 of the memory cartridge 60 . This data can be loaded into the FPGA 45 from an external computer by modifying the boot program of the CPU 40 .

The following is the second preferred embodiment of the Diagnostic system according to the present invention explained.

As shown in FIG. 5, the diagnostic device 100 a has a control device 36 a, which is configured as a multiple processor. The control device 36 a comprises a CPU 40 a as a main processor, a RAM 41 , a timer 42 for generating a synchronization signal, input / output interfaces 43 and 44 and a sub-processor (ISP) 70 . Via system buses, these components, and a ROM 61a of a memory cartridge 60 are a-jointed with each other. The ISP 70 sends and receives signals to and from an electronic control unit (ECU) 2 , which is in data communication with the control device 36 a via system bus se.

The CPU 40 a is a one-chip processor, while the ISP 70 is a one-chip device with a processor, ROMs, RAMs and input / output interfaces. The one-chip processor, such as the CPU 40 a, and the one-chip device, such as the ISP 70 , are both referred to as processors in the context of this invention.

The memory cartridge 60 a should make the diagnostic device 100 a flexible for general use or usable for different diagnostic objects, vehicle types, communication protocols, etc. For this purpose, the ROM 61 a stores various programs for the CPU 40 a and the ISP 70 . The programs for the CPU 40 a are a diagnostic boot program, a diagnostic program for the ECU 2 of a certain motor vehicle, etc. The programs for the ISP 70 include a communication processing program which can be adapted to the communication protocol of the ECU 2 , etc.

The memory cartridge 60 a has an input / output interface 62 a, which connects the ISP 70 and the ECU 2 . Transmission lines 63 a and 64 a are connected to the input / output interface 62 a via the connecting device 38 . The transmission lines 63 a and 64 a are also connected to the input and output interfaces 6 and 7 of the ECU 2 via an input / output connection device 33 and an adapter piece 34 .

The input / output interface 62 a adjusts signal levels, input / output powers and the like to the ECU 2 , which are different in transmission systems of the motor vehicles and cannot be emulated by software. Transmission lines 63 b and 64 b are connected via the connection device 38 to the input / output interface 62 a and extend from the output and the input connection of the ISP 70 . The input / output interface 62 a can be replaced by wires that connect the transmission lines 63 a and 63 b and 64 a and 64 b. This replacement is possible if the signals between the ECU 2 and the ISP 70 are matched to one another.

The CPU 40 a has memory areas for the programs or data which are stored in the RAM 41 of the control device 36 a and the ROM 61 a of the memory cartridge 60 a. The system of the diagnostic device 100 a runs with a start program (boot program) which is stored in the ROM 61 a. This boot program does not necessarily have to be stored in the ROM 61 a. The boot program can be stored in a ROM (not shown) of the control device 36 a. Or if the CPU 40 a is a device with an internal ROM, the boot program could also be stored in the internal ROM.

The ISP 70 enables the diagnostic device 100 a to exchange data with an electronic control unit with different communication protocols of several types of motor vehicles. So it can be said that the ISP 70 is an intelligent input / output interface of a microcomputer. In this second embodiment, the ISP 70 is a one-chip device with a ROM for storing the boot program, RAMs for storing data and input / output interfaces.

In order to diagnose errors, the memory cassette 60 a with the ROM 61 a is introduced into the diagnostic device 100 a. The ROM 61 a stores the diagnostic program for the engine control unit (ECU) 2 of a particular motor vehicle and a communication processing program.

The diagnostic device 100 a is initialized, and the communication processing program stored in the ROM 61 a is transmitted to the ISP 70 . The ISP 70 executes the communication processing program to enable data exchange with the ECU 2 . During the data exchange, the ISP 70 sends the data of the CPU 40 a to the ECU 2 and vice versa.

On the one hand, the CPU 40 reads and writes data from or to the ISP 70 in order to establish a virtual data exchange with the ECU 2 . On the other hand, the ISP 70 performs an actual data exchange with the ECU 2 , whereby the communication processing program is sent from the ROM 61 a of the memory cassette 60 a. The ISP 70 can effect the data exchange with the ECU 2 regardless of the diagnosis that is carried out by the CPU 40 a.

The ISP 70 may have a low-capacity internal memory, or it may be a one-chip processor that does not contain such internal memory. In this case, a RAM for storing the communication processing program or working data and a ROM for storing the boot program can be provided in the control device 36 a.

The flow diagrams of the flow of data exchange and diagnosis shown in FIGS. 6A and 6B are discussed below. Fig. 6A shows the first method (process), which is carried out by the CPU 40 a of the diagnostic device 100 a. Fig. 6b shows the second method (process), which is carried out by the ISP 70 of the diagnostic device 100 a.

To carry out the first and the second method: the diagnostic device 100 a with the memory cassette 60 a, which is suitable for the ECU 2 of the motor vehicle 200 , is connected via the adapter piece 34 ; then the circuit breaker 35 is turned on to reset the CPU 40 a, which controls the main system of the diagnostic device 100 a. The first method shown in FIG. 6A then begins.

In step S201, the main system of the diagnostic device 100 a is initialized. Then, in step S202, the data exchange subsystem of the ISP 70 is reset to start the second method shown in FIG. 6B. In step S301 ( FIG. 6B), the subsystem of the ISP 70 is also initialized.

In step S203, the CPU 40 (program lations Kommunikationsemu) reads a data from the ROM 61 a of the memory cartridge 60 from a. The communication emulation program is used to emulate the communication protocol of the ECU 2 . The data is written to a channel or port of the ISP 70 . The first method then goes into a data receive queue in step S204.

In the second method in FIG. 6B, the ISP 70 receives in step S302 the data of the emulation program which are transferred to its channel. The ISP 70 transfers the data to a specific memory address (the address of the internal RAM) in step S303. Then, the ISP 70 sends a data confirmation signal from its channel in step S304.

In the first method shown in FIG. 6A, the CPU 40 reads a step S204, the data confirmation signal. The first process proceeds from the data receiving queue in step S204 to step S205. In step S205, it is checked whether the data transmission has been completed. If it is completed, the first process proceeds to step S206. If it is not completed, the first process goes back to step S203 to continue the data transfer.

During steps S203 to S206 in the first method, the second method goes from step S304 to step S305. In step S305, it is checked whether the data reception has been completed. The second method proceeds to step S306 when data reception and data transfer to the ISP 70 memory are completed. If they are not completed, the second process goes back to step S302 to continue receiving data.

In the first method, the CPU 40 a in step S206 a response request to the ECU 2 writes in a channel of the ISP 70th This is done after the completion of the transmission of the communication emulation program from the CPU 40 a to the ISP 70 . The CPU 40 a then goes into a response waiting mode in step S107 to await a response from the ECU 2 .

At the same time, the ISP 70 executes the communication emulation program in step S306 in the second method. The ISP 70 reads the response request from the CPU 40 a and sends response request data to its output port. The request data are transmitted via the transmission line 63 b, the input / output interface 62 a of the memory cartridge 60 a, the transmission line 63 a and the adapter piece 34 to the ECU 2 . This transmission of the request data is carried out with the communication protocol of the ECU 2 .

The ECU 2 reads the request data via the input interface 6 . The ECU 2 then sends out response data via the input interface 7 . The response data are transmitted via the adapter piece 34 , the transmission line 64 a, the input / output interface 62 a of the memory cartridge 60 a and the transmission line 64 b to the input port of the ISP 70 . The response data is also sent from a channel of the ISP 70 to the system buses.

In the first method, the CPU 40 in step S207 reads a response data from the ISP 70, and confirms the response of the ECU. 2 The first method then goes to step S208, in which an application program for the diagnosis is executed. The "Diagnostics Start Ok" message is displayed on the screen 30 and the first method goes into a wait mode to await keyboard input from the keyboard 32 while the application program is running.

To z. B. to check a battery voltage, a Be operating position, the keys for the battery voltage diagnostic mode on the keyboard 32 , for example "F", "0", "1" and "ENT". This diagnostic mode is interpreted by the CPU 40 a, which sends a request for the battery voltage data to the ISP 70 .

The ISP 70 converts the battery voltage request data into a data exchange request signal with a certain format and a certain timing according to the communication protocol of the ECU 2 . Upon receipt, the ISP 70 receives the battery voltage data sent from the ECU 2 and sends out the data on its channel.

The CPU 40 a reads the data sent by the ISP 70 and performs data processing, e.g. B. a binary-decimal conversion. The processed result is displayed on the screen 30. The operator checks the battery voltage via the display and, if necessary, continues the diagnosis of further points by entering the appropriate keys.

As described above, the diagnostic device according to the second embodiment for different types of elek tronic control units are used. This will be there achieved by using the for the communication protocols different data formats, send and receive times etc. suitable memory cartridges. It no other diagnostic tools with different Hardware for the communication protocols of the electronic Control units are provided. This results in a very efficient diagnostic operation.

The second embodiment uses the ISP 70 as a one-chip subprocessor with a ROM, RAM and I / O interfaces. However, a single-chip processor with only one data processing unit could also be used as ISP 70 . In this case, the ROM or RAM with the storage area for the ISP 70 are seen in the control device 36 a. Furthermore, part of the ROM or RAM or part of the RAM 41 for the CPU 40 a is used as a communication buffer. This communication buffer can be used both for the transfer of in the ROM 61a of the memory cartridge 60 a ge-stored communication processing program and for exchanging data between the CPU 40 a and the ISP 70th

The control device 36 a can be equipped with a control device for direct memory access (DMA). In this case, the communication processing program can be transferred from the ROM 61 to the ISP 70 by DMA transfer.

Furthermore, the communication processing program for the ISP 70 does not necessarily have to be stored in the ROM 61 a of the memory cartridge 60 a. Another possibility is to modify the boot program for the CPU 40 a so that it is loaded together with the communication processing program from an external computer.

According to the above description, the present invention has the following advantages:
The fault diagnosis device has an integrated circuit, the logic functions of which can be reprogrammed on site with design data. The integrated circuit is used as a communication interface that is suitable for communication protocols of an electrical control unit that is mounted in a motor vehicle. The diagnostic device carries out a diagnosis on the basis of the data which are sent by the electronic control unit which carries out a data exchange in accordance with the communication protocol. The diagnostic device according to the present invention can thus be used for different types of electronic control units with different communication protocols. As a result, the diagnostic device can be used universally and flexibly, and the costs for the diagnosis are reduced.

The design data for the integrated circuit which the communication interface forms are also in one Recording medium in a removable cassette stores. The diagnostic device can thus differ che communication protocols for various electronic Control units are adapted, which in motor vehicles are installed. The diagnostic program is also on the same Recording media stored in the removable cassette chert. So the program can easily be incorporated into a diagnostic program be converted to an electronic control unit a motor vehicle is adapted. This results in one versatile usability for diagnosis.

The integrated circuit, which is the communication interface is also via an interface circuit in the cassette with the electronic control unit of the motor vehicle connected. With this interface circuit are signal level, input / output power conditions and the like, which differ from the communication system distinguish stem of the motor vehicle and which by the communication protocol can be adapted, so vice versa be converted to the electronic control unit fit.

The present invention also has the following advantages:
The communication processing program can be converted externally into a suitable program for the communication protocol of an electronic control unit which is mounted in a motor vehicle. The subprocessor executes the communications processing program, with data exchange taking place with the electronic control unit. And the main processor exchanges data with the subprocessor for diagnosis. This means that the main processor performs a virtual data exchange with the electronic control unit. The diagnostic device can therefore be used for different types of electronic control units with different communication protocols without changing their hardware. As a result, the diagnostic device can be used flexibly and the costs for the diagnosis are reduced.

The communication processing program for the subpro processor is also in a recording medium in a cas sette saved. This allows the saved program in a communication processing program to be converted which to the communication protocol of an electronic Control unit mounted in a motor vehicle, fits. The diagnostic program for the main processor is too on the same recording medium in the cassette stores. This means that this stored program can also be saved in a diagnostic program can be converted, which leads to the com communication protocol of an electronic control unit in fits a motor vehicle. The installation of the Programs on the same recording medium have a high slide gnosefähigkeit.

The execution of the diagnostic program by the main process sor and the execution of the communication processing pro grams by the subprocessor are also with their egg gene storage areas performed. The diagnostic processing processing and communication processing become independent gig from each other. This results in a high one Processing capacity.

The subprocessor is also via an interface scarf device in the cassette with the mounted in the motor vehicle  electronic control unit connected. With this cut signal circuit, input / output lei stungen and the like, which in the communication system of the vehicles are different and which are not compensated by adapting the communication protocols to any electronic control unit customized.

While here are the currently preferred embodiments of the present invention has been shown and described note that this disclosure is for the purpose of explanation only serves and that various changes and modifications tion can be carried out without the scope of the inven leave according to the following claims.

Claims (5)

1. Diagnostic system, which can optionally be connected to one of several electronic control units for data transmission, each control unit having a special transmission protocol, with the following features:
a main processor ( 40 ) for issuing a command to the electronic control unit ( 2 ) and processing data which are transmitted depending on the command from the electronic control unit ( 2 );
a transmission interface ( 45 ) which is provided between the main processor ( 40 ) and the electronic control unit ( 2 ) and is reprogrammable on site; and
a memory cartridge ( 60 ) which is detachably connected to the main processor ( 40 ) and has a memory ( 61 ) with design data, which the main processor ( 40 ) for reprogramming the transmission interface ( 45 ) when the diagnostic system is activated to adapt the transmission interface ( 45 ) to the special transmission protocol of the electronic control unit ( 2 ) so that the diagnostic system can exchange data with different electronic control units that have different transmission protocols. 2. Diagnostic system according to claim 1, wherein the transmission interface ( 45 ) has a volatile or non-volatile memory ( 46 ) for storing the transmitted De signdaten. 3. Diagnostic interface according to claim 1 or 2, wherein the transmission interface ( 45 ) is a user-programmable universal circuit. 4. Diagnostic system, which can optionally be connected to one of several electronic control units ( 2 ) for data transmission, each control unit ( 2 ) having a special transmission protocol, with the following features:
a main processor ( 40 a) for issuing a command directed to the electronic control unit ( 2 ) and for processing data which are transmitted depending on the command from the electronic control unit ( 2 );
a subprocessor ( 70 ), which is provided between the main processor ( 40 a) and the electronic control unit ( 2 ) and an on-site reprogrammable transmission processing program; and
a memory cartridge ( 60 a) which is detachably connected to the main processor ( 40 a) and a memory ( 61 a) with data of the transmission processing program, which, when the diagnostic system is activated, from the main processor ( 40 a) to one Memory of the subprocessor ( 70 ) are transferred to reprogram the sub processor ( 70 ) to adapt it to the special transmission protocol of the electronic control unit ( 2 ), so that the diagnostic system with different electronic control units that have different transmission protocols, data can exchange. 5. Diagnostic system according to claim 4, wherein the memory for the subprocessor ( 70 ) is an assigned memory area of the main processor ( 40 a).